Apple issues review guidelines for Mac App Store
“Apps that encourage excessive consumption of alcohol or illegal substances, or encourage minors to consume alcohol or smoke cigarettes, will be rejected. Apps that provide incorrect diagnostic or other inaccurate device data will be rejected. Developers ‘spamming’ the App Store with many versions of similar apps will be removed from the Mac Developer Program.
Reading through the list (and it is a long list) the guidelines for the Mac App Store are in stark contrast to how you get software now (i.e., the internet) however given some time to get established and Apple may find themselves with a whole segment of the population who don’t want to spend the time to go and download software any other way.
Read another way, is this the first steps toward developers beholden to Apple’s App Store as their portal to customers?

